# imagecropauto

(PHP 5 >= 5.5.0, PHP 7, PHP 8)

imagecropauto — Crop an image automatically using one of the available modes

### Beschreibung

imagecropauto(
GdImage `$image`,
int `$mode` = `IMG_CROP_DEFAULT`,
float `$threshold` = 0.5,
int `$color` = -1
): GdImage|false

Automatically crops an image according to the given `mode`.

### Parameter-Liste

`image`

  Ein GdImage-Objekt, das von einer der Funktionen zur Bilderzeugung, z. B. imagecreatetruecolor(), zurückgegeben wurde.

`mode`

  One of the following constants:

  `IMG_CROP_DEFAULT`
    Same as `IMG_CROP_TRANSPARENT`. Before PHP 7.4.0, the bundled libgd fell back to `IMG_CROP_SIDES`, if the image had no transparent color.
  `IMG_CROP_TRANSPARENT`
    Crops out a transparent background.
  `IMG_CROP_BLACK`
    Crops out a black background.
  `IMG_CROP_WHITE`
    Crops out a white background.
  `IMG_CROP_SIDES`
    Uses the 4 corners of the image to attempt to detect the background to crop.
  `IMG_CROP_THRESHOLD`
    Crops an image using the given `threshold` and `color`.
`threshold`

  Specifies the tolerance in percent to be used while comparing the image color and the color to crop. The method used to calculate the color difference is based on the color distance in the RGB(a) cube.

  Used only in `IMG_CROP_THRESHOLD` mode.

  > Hinweis: Before PHP 7.4.0, the bundled libgd used a somewhat different algorithm, so the same `threshold` yielded different results for system and bundled libgd.

`color`

  Either an RGB color value or a palette index.

  Used only in `IMG_CROP_THRESHOLD` mode.

### Rückgabewerte

Returns a cropped image object on successBei einem Fehler wird `false` zurückgegeben.. `false` is also returned if the whole image was cropped.

### Changelog

Version | Beschreibung
--- | ---
8.0.0 | `image` erwartet nun eine GdImage-Instanz; vorher wurde eine gültige `gd`-Ressource erwartet.
8.0.0 | On success, this function returns a GDImage instance now; previously, a resource was returned.
7.4.0 | The behavior of imagecropauto() in the bundled libgd has been synced with that of system libgd: `IMG_CROP_DEFAULT` no longer falls back to `IMG_CROP_SIDES` and threshold-cropping now uses the same algorithm as system libgd.
7.4.0 | The default value of `mode` has been changed to `IMG_CROP_AUTO`. Formerly, the default value has been `-1` which corresponds to `IMG_CROP_DEFAULT`, but passing `-1` is now deprecated.

### Beispiele

Beispiel #1 Proper handling of auto-cropping

As noted in the return value section, imagecropauto() returns `false` if the whole image was cropped. In this example we have an image object `$im` which should be automatically cropped only if there is something to crop; otherwise we want to proceed with the original image.

`<?php
$cropped = imagecropauto($im, IMG_CROP_DEFAULT);
if ($cropped !== false) { // in case a new image object was returned
$im = $cropped; // assign the cropped image to $im
}
?>`

### Siehe auch

- imagecrop() - Crop an image to the given rectangle

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